Sleep disorders and sleep disturbances are those known to be included in the definition by those skilled in the art, which includes e.g. insomnia, agitation, restlessness.
Benzodiazepines are widely used in the pharmacological treatment of sleep disorders and/or sleep disturbances . These compounds are endowed with numerous side effects such as amnesia, induction of tolerance and high abuse potential. Thus there exists a need for a compound in the treatment sleep disorders and/or sleep disturbances which causes less side effects than known compounds.
Preclinical experiments have shown that dopamine D1 receptor antagonists, including NNC 0756 ((+-8-chloro-7-hydroxy-3-methyl-5-(2,3-dihydrobenzofuran-7-yl)-2,3,4,5-tet rahydro-1H-3-benzazepine) markedly enhance the time spent in sleep through an increase in both REM and non-REM sleep ("Differential effects of dopamine D1 and D2 receptor antagonist antipsychotics on sleep-wake patterns in the rat", Ongini et al. (1993), Journ. Pharm. Exp. Ther., 266 (2), 726-731) whereas the dopamine D1 receptor agonist SKF 38393 reduced the amount of REM sleep and increased the duration of wakefulness ("The dopamine D1 receptor is involved in the regulation of REM sleep in the rat", Trampus et al. (1991), Eur. Journ. Pharm., 194, 189-194).
Ideally, a hypnotic should have a short half life, so that the compound, when administered at bed time, is cleared from the body in the morning. Therefore, compounds like NNC 0756, having a relatively long half life, is not well suited with respect to this indication.
In EP 5,298 and EP 5,299, 7-hydroxy-2,3,4,5-tetrahydro-1H-3-benzazepine derivatives are described. It is stated that these compounds have antipsychotic and antidepressive effects.
In European Patent No. 0200455, 8-chloro-2,3,4,5-tetrahydro-1H-3-benzazepines including NNC 0756 (+)-8-chloro-7-hydroxy-3-methyl-5-(2,3-dihydrobenzofuran-7-yl)-2,3,4,5-tet rahydro-1H-3-benzazepine are described These compounds are described as dopamine antagonists having antipsychotic and antidepressive effects.
European Patent No. 0347672 describes 8-nitro-2,3,4,5-tetrahydro-1H-3-benzazepines. These compounds are described as dopamine antagonists useful as neuroleptics in the treatment of various mental disorders, e.g manic-depressive disorders. There is no disclosure in the application of using the compounds to treat sleep disorders.
One object of the present invention is to provide compounds which can effectively be used in the treatment or prevention of sleep disorders and/or sleep disturbances, e.g. insomnia, and which have a short half life, so that the compounds, when administered at bed time, are cleared from the body in the morning.